Indicia reading terminal including optical filter

ABSTRACT

Embodiments of the present invention comprise an indicia reading terminal that is operatively configured to decode visible and non-visible decodable indicia. The terminal can comprise an excitation illumination module for illuminating the decodable indicia with light that has a wavelength selected so as to permit the decodable indicia to emit light. The terminal can also comprise a filter module with an optical filter that has filter regions configured to pass certain wavelengths of light. The terminal can also comprise an image sensor module with an image sensor located so as to receive light emitted from the decodable indicia from the filter region.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. Patent ApplicationNo. 14/166,103 for an Indicia Reading Terminal Including Optical Filterfiled Jan. 28, 2014 (and published Oct. 23, 2014 as U.S. PatentPublication No. 2014/0312121), now U.S. Pat. No. 9,292,723, which claimsthe benefit of U.S. patent application Ser. No. 13/057,236 for anIndicia Reading Terminal Including Optical Filter filed Aug. 10, 2012(and published Nov. 29, 2012 as U.S. Patent Publication No.2012/0298755), now U.S. Pat. No. 8,640,958, which itself claims thebenefit of International Application No. PCT/CN2010/000089 for anIndicia Reading Terminal Including Optical Filter filed Jan. 21, 2010(and published Jul. 28, 2011 as WIPO Publication No. WO 2011/088590).Each of the foregoing patent applications, patent publications, andpatents is hereby incorporated by reference in its entirety.

FIELD OF THE INVENTION

The present invention relates to indicia reading terminals, and moreparticularly, to indicia reading terminals operatively configured todecode decodable indicia printed with material responsive to bothvisible and non-visible (e.g., ultraviolet (“UV”)) light.

BACKGROUND

Indicia reading terminals are available in multiple varieties.Well-known among the varieties is the gun style terminal as commonlyseen at retail store checkout counters. Other terminals are alsoavailable that provide enhanced functions, have keyboards, and displays,and include advanced networking communication capabilities. Many indiciareading terminals also have triggers for activating decoding attempts.

Typically indicia reading terminals are implemented to decode decodableindicia that are readily visible. Advances in security and similarprecautionary protocols tend, however, to utilize decodable indicia thatare only visible in the presences of non-visible light such as UV light.These non-visible indicia are often printed with materials such as inkso that to the naked eye the indicia do not appear to be present on thedocument, package, or device.

Known devices used to decode non-visible indicia comprise UV fluorescentilluminating devices which emit UV illumination. Short wavelength diodeshave been used, for example, to emit light in the deep blue to near UVregion of the spectrum, and can be used to produce illuminationcompatible with the non-visible indicia. These devices are somewhatlimited in their application, however, because although they canilluminate the non-visible indicia, actual decoding of the indicia isparticularly sensitive to the position, orientation, and other physicalalignment between the devices and the illuminated non-visible indicia.

There is a need, therefore, for an indicia reading terminal that candecode both visible and non-visible decodable indicia, and in oneexample there is a need for such terminal that can decode these types ofindicia without substantial reduction in the depth of field of theterminal.

SUMMARY

There is described below embodiments of an indicia reading terminal thatcan be operative to decode visible and non-visible decodable indicia.Some embodiments comprise an excitation illumination module, a filtermodule, and an image sensor module, all of which are configured topermit the indicia reading terminal to decode non-visible decodableindicia at distances greater than the distances of those devicesdiscussed in the Background above.

Some of the concepts and features of the present invention are discussedin more detail below, wherein:

In one embodiment, there is provided an indicia imaging unit for imaginga decodable indicia comprising a printing material. The indicia imagingunit can comprise an excitation illumination module that comprises anillumination source for casting light onto the decodable indicia. Theindicia imaging unit can also comprise an image sensor module responsiveto the emitted light from the decodable indicia, and a filter modulereceiving the reflected light before the image sensor module. The filtermodule can comprise at least one optical filter having a pass-bandmatching the emission wavelength of the emitted light. In one example,the illumination source is operatively configured to provide the lightat a wavelength that causes the printing material to emit light at anemission wavelength visible to the human eye.

In another embodiment, there is provided an indicia reading terminal forimaging decodable indicia comprising a printed material visible inresponse to light in a non-visible spectrum. The terminal can comprisean illumination source for casting light onto the decodable indicia, thelight having a wavelength in the non-visible spectrum, the wavelengthcausing light emitted from the printing material having an emissionwavelength in a visible spectrum. The terminal can also comprise anoptical filter receiving the emitted light, the optical filter cancomprise a filter region having a pass-band matching the emissionwavelength. The terminal can further comprise an image sensor responsiveto the emission wavelength in a manner permitting decoding of thedecodable indicia, the image sensor can comprise a plurality of pixelsincluding one or more of a first subset of monochrome pixels and asecond subset of color pixels. The terminal can also comprise a handheld housing in surrounding relation to one or more of the illuminationsource, the image sensor, and the optical filter. In one example, theimage sensor defines an optical axis on which is aligned the filterregion of the optical filter, wherein said hand held terminal isoperative for manual activation by a trigger depressed by an operator.In another example, the trigger causes at least one attempt to decodethe decodable indicia. In yet another example, the handheld terminal isoperative to assign one or more of the pass-band of the optical filterand the wavelength of the light generated by the illumination sourcebased the attempt to decode the decodable indicia.

In yet another embodiment, there is provided a method of decodingdecodable indicia comprising a printed material visible in response tolight in a non-visible spectrum. The method can comprises the step ofaligning on an optical axis an image sensor and an optical filter, theoptical filter comprising at least one filter region having a pass-bandfor passing an emission wavelength of light emitted by the printingmaterial. The method can also comprise the step of generating light froman illumination source, the light having a wavelength in the non-visiblespectrum. The method can further comprise the step of setting one ormore of the wavelength of the light for illuminating the decodableindicia and the pass-band for the optical filter by correlating each ofthe wavelength and the pass-band to a successful decode of the decodableindicia.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention briefly summarized above, may be had by reference to theembodiments, some of which are illustrated in the accompanying drawings.It is to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments. Moreover, the drawings are notnecessarily to scale, emphasis generally being placed upon illustratingthe principles of certain embodiments of invention.

Thus, for further understanding of the concepts of the invention,reference can be made to the following detailed description, read inconnection with the drawings in which:

FIG. 1 is a functional block diagram illustrating an embodiment of anindicia reading terminal;

FIG. 2 is a diagram illustrating an exemplary hybrid monochrome andcolor image sensor pixel array having a first subset of monochromepixels and a second subset of color pixels;

FIG. 3 is a diagram illustrating an exemplary functional indicia imagingunit comprising an excitation illumination module, a filter module, andan imaging module;

FIG. 4 is a perspective, exploded, assembly view of an example of animaging module for use with, and comprising functional indicia imagingunit such as the functional indicia imaging unit of FIG. 3;

FIG. 5 is a perspective, assembled view of another example of an imagingmodule such as the imaging module of FIG. 4, for use with, andcomprising functional indicia imaging unit such as the functionalimaging unit of FIGS. 3 and 4;

FIG. 6 is a perspective view of an indicia reading terminalincorporating an imaging module such as the imaging modules of FIGS. 4and 5; and

FIG. 7 is a block diagram of an exemplary hardware platform forimplementation in an indicia reading terminal such as the indiciareading terminal of FIG. 6.

DETAILED DESCRIPTION

In accordance with its major aspects, and broadly stated, the presentinvention comprises concepts that improve the performance of indiciareading terminals such as by adapting such terminals to illuminate,image, and decode a decodable indicia printed with, e.g., ultravioletflorescent inks. There is provided in the discussion below, for example,embodiments of an indicia reading terminal that comprise an excitationillumination module for illuminating the indicia, a filter module forfiltering light reflected from the indicia, and an image sensor modulefor receiving light from the filter module. These modules can beincorporated into an image module as seen in the exemplary image moduleof FIGS. 4 and 5 below. This configuration, as well as the combinationof the modules as a functional indicia imaging unit is beneficialbecause the inventors have found that implementing these concepts aspart of the indicia reading terminal adapts the terminal for robustdecoding of “invisible” decodable indicia without substantialdegradation of the terminal's other operating characteristics, e.g., thedepth of field, and the focal length. Moreover, in addition tomaintaining these operating characteristics while expanding the range ofapplications, such terminals can significantly improve the quality ofimages captured from the invisible indicia, and in one example theimprovement is seen in the clarity or “snappiness” of the imagesgenerated by the terminal. The term “invisible” as used herein isgenerally meant to identify decodable indicia that can be viewed withthe human eye when aided by certain excitation illumination, details ofwhich are discussed throughout the disclosure below.

To illustrate some of these concepts reference can be had to an indiciareading terminal 100 that is illustrated in the functional block diagramof FIG. 1. Here it is seen that the indicia reading terminal 100 cancomprise an indicia imaging unit 102 with an excitation illuminationmodule 104, a filter module 106, and an image sensor module 108. Othercomponents of the indicia reading terminal 100 will be discussed in moredetail below, such as, for example, in connection with the variousembodiments of image modules and terminals that are shown in FIGS. 4-7.Before getting to those more detailed examples, however, some of thefeatures, functions, and aspects of the modules in the indicia imagingunit 102 will be described immediately below.

For example, it was mentioned briefly above that the excitationillumination module 104 can be used to cast illumination onto thedecodable indicia. This illumination can originate from an excitationillumination light source that generates light, which as the term“light” is used herein means those electromagnetic wavelengths in thevisible and non-visible spectrum. An example of these electromagneticwavelengths can include UV light, infra-red (“IR”) light, othernon-visible light, as well as other light selected based on theproperties of the printing material used to create the decodableindicia. These printing materials can comprise inks such as inks that,while not visible to the human eye, emit light when excited by theexcitation illumination light source. These inks are generallywell-known and one skilled in the indicia reading arts will be readilyable to understand the properties of the printing materials for use inprinting the decodable indicia.

Light from the excitation illumination light source that is compatiblewith the printing materials can emanate from light sources that compriseone or more light emitting diodes (“LEDs”). These LEDs can comprise LEDsof a single color (e.g., UV LEDs), or they can comprise differentlycolored LEDs, the light from which can be combined to so that theoverall color emitted by the light source can be controlled and varied.In other embodiments, some examples of which are described in moredetail below, the excitation illumination light source can beoperatively configured to generate laser light such as can be done withLEDs and/or laser diodes.

The inventors have discovered that although light from traditionaltechniques such as “black-light” techniques (that utilize UV light)could be used to illuminate certain types of printing materials, thisillumination does not generally permit the indicia reading terminal 100to generate consistent good decodes of the corresponding decodableindicia over a substantially larger depth of field. Indeed the use of UVlight, IR light, and light of similar wavelength and/or frequency toilluminate the decodable indicia can limit the operating characteristicsof the terminals because the terminal oftentimes has to be placed invery near proximity to the decodable indicia. That is, in one example,whereas terminals that generally implement UV light and UV-type lightcan only decode decodable indicia printed with invisible printingmaterials when in contact with the decodable indicia, terminals such asthe indicia reading terminal 100 of the present invention can decodethese same (or similar) decodable indicia at distances of more than 20cm away from the terminal.

One aspect of the present invention that helps to overcome thisdeficiency is that the indicia reading terminal 100 incorporates thefilter module 106. The filter module 106 can be provided in someembodiments of the indicia reading terminal 100 with an optical filterthat is constructed with certain pass-bands that match the emissionwavelengths of the light emitted by the printing material. While thesepass-bands can be configured to pass light that has a wide range ofwavelengths, it is contemplated that the optical filter in certainembodiments of the indicia reading terminal 100 will comprise pass-bandsthat permit the light emitted by the printing material to pass to, e.g.,the image sensor module 108, but that effectively blocks all otherwavelengths in the visible and invisible ranges. By way of non-limitingexample, the optical filters of the filter module 106 can be positionedbetween the decodable indicia and the image sensor module 108 so thatlight emitted by (or reflected from) the decodable indicia must passthrough the optical filter before it reaches the image sensor module108. This position, when combined with construction of the opticalfilter that is based on the particular light source and/or the printingmaterials of the decodable indicia, can permit the indicia readingterminal 100 to decode the decodable indicia. This feature is beneficialbecause it permits the indicia reading terminal 100 to be located inspaced relation to the decodable indicia without degradation of itsability to achieve consistent good decodes of the decodable indicia.

Continuing with the discussion of FIG. 1, and also with reference now toFIG. 2, the image sensor module 108 (FIG. 1) can comprise an imagesensor and optics assembly, which is operatively configured to focus thelight onto the image sensor. The image sensor can comprise color ormonochrome 1D or 2D charge coupled devices (“CCD”), semiconductordevices (e.g., CMOS, NMOS, and PMOS), and other solid state imagesensors with properties and characteristics useful for capturing andprocessing image data, such as image data of a decodable indicia. Anexample of an image sensor of the type used as the image sensor in theimage sensor module 108 is illustrated in FIG. 2. There is provided inFIG. 2 a hybrid monochrome and color image sensor pixel array 200 for animaging terminal (e.g., the indicia reading terminal 100 (FIG. 1)). Thecolor image sensor pixel array 200 can include pixels arranged in aplurality of rows of pixels and can include a first subset of monochromepixels 202 devoid of color filter elements and a second subset of colorpixels 204 including color filter elements. Such color sensitive pixelscan be disposed at spaced apart positions of the color image sensorpixel array 200 and can be disposed at positions uniformly orsubstantially uniformly throughout the color image sensor pixel array200.

In one embodiment, the spaced apart color pixels of the image sensorarray, though spaced apart can follow a pattern according to a Bayerpattern. For example, where Red=R, Green=G, and Blue=B, the color pixelsshown in row 206 can have the pattern . . . GRGRGRG . . . which patterncan be repeated for rows 208 and 210. The pixels of row 212 can have thepattern . . . BGBGBGB . . . , which pattern can be repeated for row 214.The patterns described with reference to rows 206, 212, 210, 214, 208can be repeated throughout color image sensor pixel array 200.Alternatively, different patterns for the color pixels may be used inaccordance with concepts of the invention. A color frame of image datacaptured with use of a color image sensor pixel array 200 having bothcolor and monochrome pixels can include monochrome pixel image data andcolor pixel image data. The image sensor of the image sensor module 108(FIG. 1) can be packaged in an image sensor integrated circuit as shownin FIG. 2. Various additional features that can be utilized with indiciareading terminal 100 (FIG. 1) are disclosed in U. S. patent applicationSer. No. 11/174,447 entitled, Digital Picture Taking Optical ReaderHaving Hybrid Monochrome And Color Image Sensor Array, filed Jun. 30,2005, incorporated herein by reference.

The majority of pixels of the image sensor array can be monochromepixels of the first subset. Color sensitive pixels of the second subsetare at spaced apart positions and can be uniformly or substantiallyuniformly distributed throughout the image sensor array. Color sensitivepixels may be distributed in the array in a specific pattern of uniformdistribution such as a period of P=4 where, for every fourth row ofpixels of the array, every fourth pixel is a color sensitive pixel asshown in FIG. 2. Alternatively, other distributions may be used such asa period of P=2, where every other pixel of every other row of the imagesensor array is a color sensitive pixel.

Referring back to FIG. 1, and continuing the discussion of some otherconcepts and components of the indicia imaging unit 102 in more detail,the excitation illumination light sources of the excitation illuminationmodule 104 can comprise a plurality light sources (not shown). Some ofthese light sources can be useful to provide an aiming pattern foroptimizing the position of the indicia imaging unit 102 with respect tothe decodable indicia. To facility image acquisition, the illuminationsources can utilize an aiming pattern generating device that can beoperatively configured to project the aiming pattern in the form of auser-visible alignment indicator that assists in optimizing the spatialrelationship between the image engine and the decodable indicia on thetarget. For example, using one or more light emitting devices (e.g.,LEDs), examples of which are provided immediately below, in conjunctionwith the appropriate or desired aiming pattern generating device, theuser may see patterns such as cross-hairs, corner brackets, one or moredots, a line, or combination of these, projected on the target bearingthe decodable indicia. These patterns can provide visual feedback to theuser to assist in placing the indicia imaging unit 102 and the targetindicia into an acceptable reading position relative to each other.

Although a variety of techniques can be used, in one example the lightsource can be provided by one or more LEDs. These LEDs can be positionedso that the light generated by the LEDs is directed in a preferredorientation (e.g., substantially perpendicular) with respect to theindicia imaging unit 102, indicia reading terminal 100, and/or othersurface(s) of, e.g., a substrate such as a printed circuit board orsemiconductor device, both of which are suited to have the LEDs affixedthereon. An opening or aperture can generally be provided such as in anoptical plate (e.g., optical plate 420 (FIG. 4)) so as to permit thelight beam to exit the indicia imaging unit 102. This aperture can besized, shaped, and configured such as in the form of a slit, annularfeature, square, rectangle, and a plurality of holes, all of which caninfluence the shape of the aiming pattern that is generated on thetarget.

Discussing now some additional features of the excitation illuminationmodule 104 and/or excitation illumination light sources, it iscontemplated that the devices such as LEDs that are used as one or moreof the light sources are operatively configured to provide substantiallyuniform illumination of the target. In the case of acquisitionillumination, the illumination light source is projected towards thetarget, such as a bar code indicia on the target, and the resultingscattering light from the target passes through the optics of theindicia imaging unit 102 such as, for example, optics and optical layerspositioned relative to the image sensor module 108. The light canimpinge on the responsive portion of the image sensor module 108. Whileconventional data collection devices that image decodable indiciavisible to the human eye employ visible light, and primarily white, red,blue, and/or green for targeting and image acquisition illumination,this is not a requirement. That is, depending on the environment of useand overall module capabilities, other wavelengths or portions of thespectrum may be used as well.

It is further noted that the amount of light, both ambient and thatgenerated by the indicia reading terminal 100, can be an importantfactor in the performance of the indicia reading terminal 100 andindicia imaging unit 102. With regard to light generated by the indiciareading terminal 100, the amount of light and the amount of powerrequired to produce it are factors in whether an image can be acquiredat all (for example, under low light and/or long range conditions); inthe time needed to acquire the image (for example, higher illuminationcan improve contrast levels, decreasing the time needed to recognizeand/or acquire an image, or conversely can produce glare or specularreflection, impairing image detection and acquisition); in the qualityof the image acquired; in whether it is necessary or desirable toalternate or combine the use of aiming illumination and acquisitionillumination sources; and, in the case of a battery-powered device, inbalancing power conservation with performance. When reading 2Dsymbologies the aiming illumination is usually turned off when an imageis being acquired in order to ensure a constant illumination over thefield of view. This may also improve power conservation. When reading 1Dbar code symbols or some 2D bar codes on the other hand, conditions suchas low ambient lighting, relatively large distances, and relatively poorquality of the indicia may favor leaving the aiming illumination on whenthe acquisition illumination is energized, effectively turning theaiming illumination into an auxiliary form of acquisition illuminationin order to maximize the light reaching the target indicia.

The uniform illumination from one or more of the light sources maycomprise, for example, an overall illuminated pattern that correspondsto the field of view of the indicia reading terminal 100. In oneparticular example, one of the light sources can be configured so thatthe overall pattern provided illuminates the corners of the field ofview to a brightness of at least about 50% of the target areas maximumbrightness. Randomization of the overall pattern such as by usingmicrolenses can reduce the formation of “hot spots,” which areconcentrated areas of constant higher radiance illumination on thetarget area. Likewise diffusion of light in a direction generallytransverse to the direction of light diffusion provided by, e.g., themicrolenses, can cause the light to diverge in relation to one anotherat typical module to target reading distances (e.g., about 1 inch to 15inches for common symbologies). Moreover, it will be appreciated thatdiffusion patterns of light generated by ones of the light sources canbe substantially manipulated using various lensing techniques, which canbe optimized and modified as desired to provide light coverage on thetarget. These modifications can be implemented as part of themanufacturing process, and/or as part of the construction of, e.g., thehand held device.

Referring now to FIG. 3, an exemplary arrangement of a functionalindicia imaging unit 300 is illustrated as it might be used to image adecodable indicia 302. In the present example, it is seen that thefunctional indicia imaging unit 300 can comprise an excitationillumination module 304, a filter module 306, and an image sensor module308 with an image sensor 310 defining an optical axis 312. The filtermodule 306 can be operatively positioned so that light reflecting fromthe decodable indicia 302 impinges on the filter module 306 before thelight reaches the image sensor 310.

The filter module 306 can comprise an optical filter 314 with aplurality of filter regions 316, each of which can be configured topermit a certain wavelength (or range of wavelengths) to pass onto theimage sensor module 308. Exemplary ranges can include, for example,wavelengths consistent with red, green, and orange visible light, or asdefined by particular values of the pass-band wavelength such as 625 nm,610 nm, and 510 nm, among others. The optical filter 314 can beconstructed as a unitary structure made out of for example plastic(e.g., acrylic) that is treated and/or manufactured so as to include oneor more of the filter regions 316. Other examples of the optical filter314 can be constructed with a substrate 318, which has deposited thereoncertain types of optical materials (e.g., optical coatings, opticalfilms, optical layers), which are particularly selected so as to formthe filter regions 316. In other embodiments of the present invention,these optical materials can be disposed on, or constructed as part of,the image sensor module 308 such as part of its lens assembly (notshown) or its image sensor 310. This configuration can be implemented,in one example, by disposing optical materials on pixels (and regions ofpixels) found in the pixel array discussed in connection with the imagesensor of FIG. 2.

In one implementation of the functional indicia imaging unit 300,actuators (e.g., a piezoelectric actuator) can be used to move theoptical filter 314. These actuators can translate, rotate, oscillate,and otherwise act upon all or a portion of the optical filter 314 so asto locate the different filter regions 316 in a position to interceptthe light reflected from the decodable indicia 302. One location, forexample, may align individual ones of the filter regions 316 with theoptical axis 312. Moreover, during operation of the terminal (e.g.,indicia reading terminal 100 (FIG. 1)) it is contemplated that theselection of the filter regions 316 can be orchestrated as part of thedecode process of the terminal device. This process may comprise a stepfor attempting to decode the decodable indicia 302 using one of thefilter regions 316 and an illumination setting for the excitationillumination module 304. If the attempt fails, the process may alsocomprise a step for changing one or more of the filter regions 316 andthe illumination setting and attempting to decode again. The process mayend when a successful combination of the filter regions 316 andillumination settings permits the terminal device to successfully decodethe decodable indicia 302.

It was noted above that each of the modules, and collectively thefunctional indicia imaging unit, can be incorporated into the imagingmodule for use in the indicia reading terminal. An example of an imagingmodule 400 is illustrated in FIGS. 4 and 5, and described in more detailbelow. In one embodiment, the imaging module 400 can comprise an imagesensor module 402 comprising a lens assembly 404, and an image sensor406 defining an optical axis 408. The image sensor 406 is disposed on aprinted circuit board 410 together with an excitation illuminationmodule 412, which can comprise one or more of an illumination patternlight source bank 414, and aiming pattern light source bank 416. Both ofthe pattern light source banks 414, 416 can be provided in this exampleas a single light source. The imaging module 400 can also comprise atleast one filter module 418 that can be aligned with the optical axis408. The imaging module 400 can further include an optical plate 420that can have optics for shaping light from illumination pattern lightsource bank 414, and the aiming pattern light source bank 416 intopredetermined patterns.

Imaging module 400 can be disposed in an indicia reading terminal 600,an example of which is shown in FIG. 6. The indicia reading terminal 600can include a hand held housing 602 that supports a user input interface604 with a pointer controller 606, a keyboard 608, a touch panel 610,and a trigger 612. The hand held housing 602 can also support a useroutput interface 614 with a display 616.

Exemplary devices that can be used for devices of the user inputinterface 604 are generally discussed immediately below. Each of theseis implemented as part of, and often integrated into the hand heldhousing 602 so as to permit an operator to input one or more operatorinitiated commands. These commands may specify, and/or activate certainfunctions of the indicia reading terminal. They may also initiatecertain ones of the applications, drivers, and other executableinstructions so as to cause the indicia reading terminal 1000 to operatein an operating mode.

Devices that are used for the point controller 606 are generallyconfigured so as to translate the operator initiated command into motionof a virtual pointer provided by a graphical user interface (“GUI”) ofthe operating system of the indicia reading terminal 600. It can includedevices such as a thumbwheel, a roller ball, and a touch pad. In someother configurations, the devices may also include a mouse, or otherauxiliary device that is connected, e.g., via wire, or wirelesscommunication technology, to the indicia reading terminal 600.

Implementation of the keyboard 608 can be provided using one or morebuttons, which are presented to the operator on the hand held housing602. The touch panel 610 may supplement, or replace the buttons of thekeyboard 608. For example, one of the GUIs of the operating system maybe configured to provide one or more virtual icons for display on, e.g.,the display 616, or as part of another display device on, or connectedto the indicia reading terminal 600. Such virtual icons (e.g., buttons,and slide bars) are configured so that the operator can select them,e.g., by pressing or selecting the virtual icon with a stylus (notshown) or a finger (not shown).

The virtual icons can also be used to implement the trigger 612. On theother hand, other devices for use as the trigger 612 may be supportedwithin, or as part of the hand held housing 602. These include, but arenot limited to, a button, a switch, or a similar type of actionablehardware that can be incorporated into the embodiments of the indiciareading terminal 600. These can be used to activate one or more of thedevices of the portable data terminal, such as the bar code readerdiscussed below.

Displays of the type suited for use on the indicia reading terminal 600are generally configured to display images, data, and GUIs associatedwith the operating system and/or software (and related applications) ofthe indicia reading terminal 600. The displays can include, but are notlimited to, LCD displays, plasma displays, LED displays, among manyothers and combinations thereof. Although preferred construction of theindicia reading terminal 600 will include devices that display data(e.g., images, and text) in color, the display that is selected for thedisplay 616 may also display this data in monochrome (e.g., black andwhite). It may also be desirable that the display 616 is configured todisplay the GUI, and in particular configurations of the indicia readingterminal 600 that display 616 may have an associated interactiveoverlay, like a touch screen overlay. This permits the display 616 to beused as part the GUI so as to permit the operator to interact with thevirtual icons, the buttons, and other implements of the GUI to initiatethe operator initiated commands, e.g., by pressing on the display 616with the stylus (not shown) or finger (not shown).

The hand held housing 602 can be constructed so that it has a form, or“form factor” that can accommodate some, or all of the hardware anddevices mentioned above, and discussed below. The form factor definesthe overall configuration of the hand held housing 602. Suitable formfactors that can be used for the hand held housing 602 include, but arenot limited to, cell phones, mobile telephones, personal digitalassistants (“PDA”), as well as other form factors that are sized andshaped to be held, cradled, and supported by the operator, e.g., in theoperator's hand(s) as a gun-shaped device. One exemplary form factor isillustrated in the embodiment of the indicia reading terminal 600 thatis illustrated in the present FIG. 6.

An exemplary hardware platform for use in, e.g., the indicia readingterminal 100, 600 is illustrated and described with reference to theschematic, block diagram of FIG. 7. In FIG. 7, it is seen that anindicia reading terminal 700 can include an image sensor 702 comprisinga multiple pixel image sensor array 704 having pixels arranged in rowsand columns of pixels, column circuitry 706, and row circuitry 708.Associated with the image sensor 702 can be amplifier circuitry 710, andan analog to digital converter 712 which converts image information inthe form of analog signals read out of multiple pixel image sensor array704 into image information in the form of digital signals. Image sensor702 can also have an associated timing and control circuit 714 for usein controlling, e.g., the exposure period of image sensor 702, and/orgain applied to the amplifier 710. The noted circuit components 702,710, 712, and 714 can be packaged into a common image sensor integratedcircuit 716. In one example, image sensor integrated circuit 716 can beprovided by an MT10V022 image sensor integrated circuit available fromMicron Technology, Inc. In another example, image sensor integratedcircuit 716 can incorporate a Bayer pattern filter. In such anembodiment, CPU 718 prior to subjecting a frame to further processingcan interpolate pixel values intermediate of green pixel values fordevelopment of a monochrome frame of image data. In other embodiments,red, and/or blue pixel values can be utilized for the image data.

In the course of operation of the indicia reading terminal 700 imagesignals can be read out of image sensor 702, converted and stored into asystem memory such as RAM 720. A memory 722 of indicia reading terminal700 can include RAM 720, a nonvolatile memory such as EPROM 724, and astorage memory device 726 such as may be provided by a flash memory or ahard drive memory. In one embodiment, indicia reading terminal 700 caninclude CPU 718 which can be adapted to read out image data stored inmemory 722 and subject such image data to various image processingalgorithms. Indicia reading terminal 700 can include a direct memoryaccess unit (DMA) 728 for routing image information read out from imagesensor 702 that has been subject to conversion to RAM 720. In anotherembodiment, indicia reading terminal 700 can employ a system busproviding for bus arbitration mechanism (e.g., a PCI bus) thuseliminating the need for a central DMA controller. A skilled artisanwould appreciate that other embodiments of the system bus architectureand/or direct memory access components providing for efficient datatransfer between the image sensor 702 and RAM 720 are within the scopeand the spirit of the invention.

Referring to further aspects of indicia reading terminal 700, indiciareading terminal 700 can include an imaging lens assembly 730 forfocusing an image of a decodable indicia 732 located within a field ofview 734 on a substrate 736 onto image sensor 702. Imaging light rayscan be transmitted about an optical axis 740. Indicia reading terminal700 can also include an excitation illumination module 742 thatcomprises one or more of an illumination pattern light source bank 744for generating an illumination pattern 746 substantially correspondingto the field of view 734 of indicia reading terminal 700, and an aimingpattern light source bank 748 for generating an aiming pattern 750 onsubstrate 736. In use, indicia reading terminal 700 can be oriented byan operator with respect to a substrate 736 that bears the decodableindicia 732 in such manner that aiming pattern 750 is projected on adecodable indicia 732. In the example of FIG. 7, the decodable indicia732 is provided by a 1D bar code symbol. Decodable indicia could also beprovided by 2D bar code symbols or optical character recognition (OCR)characters.

The indicia reading terminal 700 can further include a filter module 752that comprises one or more optical filters 754, as well as in someembodiments an actuator assembly 756 that is coupled generally to thefilter module 752 such as to the optical filters 754. The opticalfilters 754 can be located on either side of the lens assembly 730.Likewise, one or more of the optical filters 754 can be disposed on oneor more surfaces of the lens assembly 730 and/or the image sensor 702.

Each of illumination pattern light source bank 744 and aiming patternlight source bank 748 can include one or more light sources. Lensassembly 730 can be controlled with use of lens assembly control circuit758 and the excitation illumination module 742 comprising illuminationpattern light source bank 744 and aiming pattern light source bank 748can be controlled with use of illumination assembly control circuit 760.Filter module 752 can be controlled with use of a filter module controlcircuit 762, which can be coupled to the actuator assembly 756. Lensassembly control circuit 758 can send signals to lens assembly 730,e.g., for changing a focal length and/or a best focus distance of lensassembly 730. Illumination assembly control circuit 760 can send signalsto illumination pattern light source bank 744, e.g., for changing alevel of illumination output by illumination pattern light source bank744.

Indicia reading terminal 700 can also include a number of peripheraldevices such as display 764 for displaying such information as imageframes captured with use of indicia reading terminal 700, keyboard 766,pointing device 768, and trigger 770 which may be used to make activesignals for activating frame readout and/or certain decoding processes.Indicia reading terminal 700 can be adapted so that activation oftrigger 770 activates one such signal and initiates a decode attempt ofthe decodable indicia 732. The activation of trigger 770 can alsoactivate the actuator assembly 756 in manner that locates one of thefilter regions (e.g., filter regions 316 (FIG. 3)) of the opticalfilters 754 along the optical axis 740. This function of the trigger 770can coincide with changes to the illumination from the excitationillumination module 742.

Indicia reading terminal 700 can include various interface circuits forcoupling several of the peripheral devices to system address/data bus(system bus) 772, for communication with CPU 718 also coupled to systembus 772. Indicia reading terminal 700 can include interface circuit 774for coupling image sensor timing and control circuit 714 to system bus772, interface circuit 776 for coupling the lens assembly controlcircuit 758 to system bus 772, interface circuit 778 for coupling theillumination assembly control circuit 760 to system bus 772, interfacecircuit 780 for coupling the display 764 to system bus 772, interfacecircuit 782 for coupling keyboard 766, pointing device 768, and trigger770 to system bus 772, and interface circuit 784 for coupling the filtermodule control circuit 762 to system bus 772.

In a further aspect, indicia reading terminal 700 can include one ormore I/O interfaces 786, 788 for providing communication with externaldevices (e.g., a cash register server, a store server, an inventoryfacility server, a indicia reading terminal 700, a local area networkbase station, a cellular base station). I/O interfaces 786, 788 can beinterfaces of any combination of known computer interfaces, e.g.,Ethernet (IEEE 802.3), USB, IEEE 802.11, Bluetooth, CDMA, and GSM.

It is contemplated that numerical values, as well as other values thatare recited herein are modified by the term “about”, whether expresslystated or inherently derived by the discussion of the presentdisclosure. As used herein, the term “about” defines the numericalboundaries of the modified values so as to include, but not be limitedto, tolerances and values up to, and including the numerical value somodified. That is, numerical values can include the actual value that isexpressly stated, as well as other values that are, or can be, thedecimal, fractional, or other multiple of the actual value indicated,and/or described in the disclosure.

While the present invention has been particularly shown and describedwith reference to certain exemplary embodiments, it will be understoodby one skilled in the art that various changes in detail may be effectedtherein without departing from the spirit and scope of the invention asdefined by claims that can be supported by the written description anddrawings. Further, where exemplary embodiments are described withreference to a certain number of elements it will be understood that theexemplary embodiments can be practiced utilizing either less than ormore than the certain number of elements.

The invention claimed is:
 1. A terminal, comprising: an illuminationsource for casting light onto a target, the cast light having a firstwavelength in a non-visible spectrum that causes the target to emitlight in a first visible wavelength, or a second wavelength differentfrom the first wavelength, the second wavelength being in thenon-visible spectrum that causes the target to emit light in a secondvisible wavelength different from the first visible wavelength; anoptical filter comprising a first filter region having a pass-bandmatching the first visible wavelength of the light emitted by thetarget, and a second filter region having a pass-band matching thesecond visible wavelength of the light emitted by the target; an imagesensor for generating a signal corresponding to light incident on theimage sensor, the image sensor having an optical axis on which theoptical filter is aligned; wherein the terminal is configured forattempting to process a first image of the target using the firstwavelength and the first filter region, and if processing isunsuccessful, attempting to process a second image of the target bychanging the illumination source to the second wavelength and changingthe optical filter to the second filter region.
 2. The terminal of claim1, comprising an actuator coupled to the optical filter for changing thewavelength of light that passes through the filter along the opticalaxis.
 3. The terminal of claim 1, wherein the optical filter comprises aplurality of filter regions each having a pass-band for a differentwavelength.
 4. The terminal of claim 1, comprising an actuator coupledto the optical filter, wherein: the optical filter comprises a pluralityof filter regions each having a pass-band for a different wavelength;the actuator moves the optical filter to place one of the filter regionsinto alignment with the optical axis; and the filter region aligned withthe optical axis is selected based on the wavelength of the light castby the illumination source.
 5. The terminal of claim 1, wherein theillumination source is configured for casting light at a plurality ofwavelengths.
 6. The terminal of claim 1, comprising an imaging lens forfocusing light onto the image sensor.
 7. The terminal of claim 1,comprising an imaging lens assembly optically coupled to the imagesensor, wherein: the optical filter comprises an optical coating on theimaging lens assembly; the optical coating passes light in the visiblewavelength emitted by the target.
 8. The terminal of claim 1, whereinthe optical filter blocks all wavelengths outside of the pass-band. 9.The terminal of claim 1, wherein: the image sensor comprises a pluralityof pixels; and the optical filter comprises an optical coating on apixel, the optical coating forming a filter region that passes lighthaving a visible wavelength.
 10. The terminal of claim 1, wherein; theimage sensor comprises a plurality of pixels; and the optical filtercomprises an optical coating on a plurality of pixels, wherein theoptical coating forms a plurality of filter regions each having apass-band for a different wavelength.
 11. The terminal of claim 1,wherein the illumination source comprises: a light emitting diode forgenerating a first light beam having a first wavelength for illuminatingthe target; and a laser diode for generating a second light beam oflaser light.
 12. The terminal of claim 1, wherein the image sensorcomprises a pixel array, the pixel array comprising color pixels andmonochrome pixels, the color pixels being located at spaced apartpositions on the pixel array among the monochrome pixels.
 13. Theterminal of claim 1, wherein the optical filter comprises a substratehaving separate pass-bands for wavelengths corresponding to red light,green light, and orange light.
 14. A terminal, comprising: anillumination source for casting light onto a target, the cast lighthaving a first wavelength in a non-visible spectrum that causes thetarget to emit light in a first visible wavelength, or a secondwavelength different from the first wavelength, the second wavelengthbeing in the non-visible spectrum that causes the target to emit lightin a second visible wavelength different from the first visiblewavelength; an optical filter comprising a plurality of filter regionseach having a pass-band for a different wavelength spectrum of visiblelight; an image sensor for generating a signal corresponding to lightincident on the image sensor, the image sensor having an optical axis onwhich the optical filter is aligned, the image sensor comprising a pixelarray, the pixel array comprising color pixels and monochrome pixels,the color pixels being located at spaced apart positions on the pixelarray among the monochrome pixels; wherein the terminal is configuredfor attempting to process a first image of the target using the firstwavelength and a first filter region of the plurality of filter regions,and if processing is unsuccessful, attempting to process a second imageof the target by changing the illumination source to the secondwavelength and changing the optical filter to a second filter region ofthe plurality of filter regions.
 15. The terminal of claim 14,comprising an actuator coupled to the optical filter, wherein theactuator moves the optical filter to place one of the filter regionsinto alignment with the optical axis.
 16. The terminal of claim 14,wherein the illumination source is configured for casting light at aplurality of wavelengths.
 17. The terminal of claim 14, comprising animaging lens for focusing light onto the image sensor.
 18. The terminalof claim 14, comprising an imaging lens assembly optically coupled tothe image sensor, wherein the optical filter comprises an opticalcoating on the imaging lens assembly.
 19. The terminal of claim 14,wherein the optical filter comprises an optical coating on a portion ofthe pixel array, the optical coating forming a filter region that passeslight having a visible wavelength.
 20. The terminal of claim 14,wherein: the image sensor comprises a plurality of pixels; and theoptical filter comprises an optical coating on a pixel, the opticalcoating forming a filter region that passes light having a visiblewavelength.
 21. The terminal of claim 14, wherein the illuminationsource comprises: a light emitting diode for generating a first lightbeam having a first wavelength for illuminating the target; and a laserdiode for generating a second light beam of laser light.
 22. Theterminal of claim 14, wherein the optical filter comprises a substratehaving separate pass-bands for wavelengths corresponding to red light,green light, and orange light.
 23. A method comprising: aligning anoptical axis of an image sensor with a target that emits light in avisible wavelength in response to light in a non-visible wavelengthspectrum; illuminating the target with light having a wavelength in anon-visible wavelength spectrum; and setting (i) the wavelength of thelight illuminating the target to correspond to the non-visiblewavelength spectrum in response to which the target emits light in thevisible wavelength and/or (ii) a pass-band of an optical filter alignedwith the image sensor's optical axis to correspond to the visiblewavelength in which the target emits light; generating a signalcorresponding to light incident on the image sensor by: receiving afirst trigger signal; wherein the steps of illuminating and setting areperformed in response to the first trigger signal; in response to thefirst trigger signal, attempting to process a first image of the targetbased on the signal generated by the image sensor; and in response to afailed attempt to process the first image, setting (i) the wavelength ofthe light illuminating the target to a different wavelength than thepreviously set wavelength of light illuminating the target and/or (ii) apass-band of an optical filter aligned with the image sensor's opticalaxis to correspond to a different wavelength than the previously setwavelength of the pass-band.
 24. The method of claim 23, comprisingaligning a filter region of the optical filter with the image sensor'soptical axis.
 25. The method of claim 23, wherein the optical filtercomprises a plurality of filter regions each having a pass-band for adifferent wavelength, the method comprising: selecting a filter regionbased on the wavelength of the light illuminating the target; andaligning the selected filter region with the image sensor's opticalaxis.
 26. The method of claim 23, comprising receiving a first triggersignal, wherein the steps of illuminating and setting are performed inresponse to the first trigger signal.